That Was Easy- Training in Zone 1 & 2 to Build Aerobic Capacity

When, why and how to train “easy” to maximize your aerobic benefit in triathlon.

When, why and how to train “easy” to maximize your aerobic benefit

Easy. Zone 1. All day pace. Extensive endurance. Light. 

All of the above are common words we use to describe easy endurance pace aerobic training. None are wrong. As a newer athlete (and even some of us older ones…) learning the value of Easy training is critical. If you stick around this sport long enough, you will find MOST of your training in that range. 

Slow Down Buddy

I know…you are a “hard charging, Type A who loves to train” the old “no pain no gain” mentality. Well ya know what, chill out. 

There have been hundreds of studies on elite endurance athletes, and the one thing that sticks out as a general consensus is that over 80% of their training time is done at a very easy pace (relative to their ability). 

The east African runners are famous for the “Kenyan shuffle”. In nordic skiing we call it a “ski walk”. I bet if a local pro cyclist came to your town, you could easily keep up with them on their Easy days. The saying is, “We go 30k per hour on easy days on the flats. Then also 30k per hour uphill on the hard days”. Good athletes spend a lot of time training “Easy”. 

For newer multisport folks, you are inundated with all sorts of technology to make training better. It’s a great time to be an athlete for sure…but, be ok keeping things very simple for a good long time. 

If I had my choice, new athletes would go off of three simple zones. all based on the modified Borg RPE scale of 1-10, with 9-10 being “all out” 80-85% of their training would be in that first, Easy zone.

  • Easy – about a 1-3 on the RPE scale
  • Steady – about a 3-6 on the RPE scale
  • Strong – for efforts >6 on the RPE scale 

But Why Slow, I Just Wanna Go Fast

As a new athlete, you will make LOTS of improvement over many months if you stick to solely Easy with the occasional Steady session. Heck, even us elder statesmen of the sport can get a long way with that schema, we tend to just go a bit quicker at those zones. 

We know that aerobic adaptations happen on a curve. Sure, you can get a bit more of some of those adaptations by training in a higher zone…but along with those adaptations come things like – increased fatigue, increased inflammation, more carbohydrate usage, etc. 

In addition, lower zone training helps develop different energy systems, helping athletes better utilize fat and even lactic acid for fuel and be less reliant on glycogen. 

There are even some studies that show doing too many of those sessions might actually set back basic aerobic development. Triathlon (especially long course triathlon) is MAINLY an aerobic sport. The rule of thumb is always – keep easy days easy, so the hard days can be hard. 

So What Does Easy Mean?

Now how do we qualify “Easy”, you ask? 

From a subjective standpoint, it’s pretty simple – we use the “talk test”.

Basically, it means can you at any time in the session, carry a complete and unbroken conversation? If the answer is “yes” I’d guess you are VERY close to the correct range. If you answer “no” then you are trending into the Steady and maybe even Strong zone. 

Now let’s try to quantify Easy with some paces or technology.

All Training: 

Generally, for a heart rate based session, we would say any session with an average heart rate (HR) of ~77-80% of threshold HR or lower, is a truly Easy session. Remember HR can be affected by many things like – caffeine, sleep status, hydration, heat, etc., so be mindful of that. If you are doing an Easy day on the first 90 degree summer day, your HR will be high. This is a sign of stress to the body and reason enough to ease up a bit. 


You have a pace clock right on the pool deck and a known distance.  If your 10 x 100 best average is  1:30/per 100 pace, then we would back off about 5-7sec per 100 for a truly Easy swim set or session. Swimming has a small delta between Easy and Strong because the water is constant and if you go much slower technique breaks down. If you find you cannot maintain good form, add a pull buoy or some “cheater shorts” to those easy sessions. 


For cyclists with power meters, you have a great tool to quantify the training. But…we often want to chase watts (heck we all like higher watts, no?). So, while I prescribe more rate of perceived exertion (RPE) and HR for really easy days, if you can keep average power at or BELOW 60-65% of functional threshold power (FTP), it’s going to be a pretty easy day. 


On the runs, you can use RPE and HR. If you have run some events you can use an online Vdot Calculator to spit out some training zones for you. Usually a good starting point is somewhere around 1:45 to 2:00 minutes per mile SLOWER than your average pace from a recent 5K.  

If you are super technical and have access to an invasive test like an Inscyd or Lactate based ramp test – then easy for you is very near 1mmol of blood lactate. 

In summary – be ok with Easy training, it should be your default range if life gets stressful, if you feel extra tired or if you lack “mojo”. You get good adaptations there with limited negative responses. Trust YOUR instincts on what Easy should feel like and then use your technology to validate those ranges during or after sessions. If you do that often, you will become a better athlete over a gradual amount of time and enjoy the process of doing so. 

. . .

Kurt Perham is the Founder and Head Coach of PBM Coaching. With an endurance sports career spanning nearly 30 years, Kurt has done and seen it all. He has raced at a high level in cycling, triathlon and nordic skiing. Kurt has worked with athletes of all abilities, from first timers to IM World Champions. Kurt continues to race and train at a high level as a Masters athlete, all while balancing his passion for sport with the raising of his 3 children.